A report on Chemical element

The chemical elements ordered in the periodic table
Estimated distribution of dark matter and dark energy in the universe. Only the fraction of the mass and energy in the universe labeled "atoms" is composed of chemical elements.
Periodic table showing the cosmogenic origin of each element in the Big Bang, or in large or small stars. Small stars can produce certain elements up to sulfur, by the alpha process. Supernovae are needed to produce "heavy" elements (those beyond iron and nickel) rapidly by neutron buildup, in the r-process. Certain large stars slowly produce other elements heavier than iron, in the s-process; these may then be blown into space in the off-gassing of planetary nebulae
Abundances of the chemical elements in the Solar System. Hydrogen and helium are most common, from the Big Bang. The next three elements (Li, Be, B) are rare because they are poorly synthesized in the Big Bang and also in stars. The two general trends in the remaining stellar-produced elements are: (1) an alternation of abundance in elements as they have even or odd atomic numbers (the Oddo-Harkins rule), and (2) a general decrease in abundance as elements become heavier. Iron is especially common because it represents the minimum energy nuclide that can be made by fusion of helium in supernovae.
Mendeleev's 1869 periodic table: An experiment on a system of elements. Based on their atomic weights and chemical similarities.
Dmitri Mendeleev
Henry Moseley

Species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species.

- Chemical element
The chemical elements ordered in the periodic table

148 related topics with Alpha



Periodic table

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3D views of some hydrogen-like atomic orbitals showing probability density and phase (g orbitals and higher are not shown)
Idealized order of shell-filling (most accurate for n  ≲ 4.)
Trend in atomic radii
Graph of first ionisation energies of the elements in electronvolts (predictions used for elements 105–118)
Trend in electron affinities
Flowing liquid mercury. Its liquid state at room temperature is a result of special relativity.
A periodic table colour-coded to show some commonly used sets of similar elements. The categories and their boundaries differ somewhat between sources. Alkali metals
 Alkaline earth metals
 Transition metals Other metals
 Other nonmetals
 Noble gases
Mendeleev's 1869 periodic table
Mendeleev's 1871 periodic table
Dmitri Mendeleev
Henry Moseley
Periodic table of van den Broek
Glenn T. Seaborg
One possible form of the extended periodic table to element 172, suggested by Finnish chemist Pekka Pyykkö. Deviations from the Madelung order (8s < < 6f < 7d < 8p) begin to appear at elements 139 and 140, though for the most part it continues to hold approximately.
Otto Theodor Benfey's spiral periodic table (1964)
Iron, a metal
Sulfur, a nonmetal
Arsenic, an element often called a semi-metal or metalloid

The periodic table, also known as the periodic table of the (chemical) elements, is a tabular display of the chemical elements.

Atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy vol. 1 (1808)


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Atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy vol. 1 (1808)
The Geiger–Marsden experiment:
Left: Expected results: alpha particles passing through the plum pudding model of the atom with negligible deflection.
Right: Observed results: a small portion of the particles were deflected by the concentrated positive charge of the nucleus.
The Bohr model of the atom, with an electron making instantaneous "quantum leaps" from one orbit to another with gain or loss of energy. This model of electrons in orbits is obsolete.
The binding energy needed for a nucleon to escape the nucleus, for various isotopes
A potential well, showing, according to classical mechanics, the minimum energy V(x) needed to reach each position x. Classically, a particle with energy E is constrained to a range of positions between x1 and x2.
3D views of some hydrogen-like atomic orbitals showing probability density and phase (g orbitals and higher are not shown)
This diagram shows the half-life (T½) of various isotopes with Z protons and N neutrons.
These electron's energy levels (not to scale) are sufficient for ground states of atoms up to cadmium (5s2 4d10) inclusively. Do not forget that even the top of the diagram is lower than an unbound electron state.
An example of absorption lines in a spectrum
Graphic illustrating the formation of a Bose–Einstein condensate
Scanning tunneling microscope image showing the individual atoms making up this gold (100) surface. The surface atoms deviate from the bulk crystal structure and arrange in columns several atoms wide with pits between them (See surface reconstruction).
Periodic table showing the origin of each element. Elements from carbon up to sulfur may be made in small stars by the alpha process. Elements beyond iron are made in large stars with slow neutron capture (s-process). Elements heavier than iron may be made in neutron star mergers or supernovae after the r-process.

An atom is the smallest unit of ordinary matter that forms a chemical element.

The three naturally-occurring isotopes of hydrogen. The fact that each isotope has one proton makes them all variants of hydrogen: the identity of the isotope is given by the number of protons and neutrons. From left to right, the isotopes are protium (1H) with zero neutrons, deuterium (2H) with one neutron, and tritium (3H) with two neutrons.


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The three naturally-occurring isotopes of hydrogen. The fact that each isotope has one proton makes them all variants of hydrogen: the identity of the isotope is given by the number of protons and neutrons. From left to right, the isotopes are protium (1H) with zero neutrons, deuterium (2H) with one neutron, and tritium (3H) with two neutrons.
In the bottom right corner of J. J. Thomson's photographic plate are the separate impact marks for the two isotopes of neon: neon-20 and neon-22.

Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) due to different numbers of neutrons in their nuclei.

The Space Shuttle Main Engine burnt hydrogen with oxygen, producing a nearly invisible flame at full thrust.


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The Space Shuttle Main Engine burnt hydrogen with oxygen, producing a nearly invisible flame at full thrust.
Depiction of a hydrogen atom with size of central proton shown, and the atomic diameter shown as about twice the Bohr model radius (image not to scale)
Hydrogen gas is colorless and transparent, here contained in a glass ampoule.
Phase diagram of hydrogen. The temperature and pressure scales are logarithmic, so one unit corresponds to a 10x change. The left edge corresponds to 105 Pa, which is about atmospheric pressure.
A sample of sodium hydride
Hydrogen discharge (spectrum) tube
Deuterium discharge (spectrum) tube
Antoine-Laurent de Lavoisier
Hydrogen emission spectrum lines in the visible range. These are the four visible lines of the Balmer series
NGC 604, a giant region of ionized hydrogen in the Triangulum Galaxy

Hydrogen is the chemical element with the symbol H and atomic number 1.

Joseph Priestley is usually given priority in the discovery.


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Joseph Priestley is usually given priority in the discovery.
Antoine Lavoisier discredited the phlogiston theory.
Robert H. Goddard and a liquid oxygen-gasoline rocket
An experiment setup for preparation of oxygen in academic laboratories
Orbital diagram, after Barrett (2002), showing the participating atomic orbitals from each oxygen atom, the molecular orbitals that result from their overlap, and the aufbau filling of the orbitals with the 12 electrons, 6 from each O atom, beginning from the lowest-energy orbitals, and resulting in covalent double-bond character from filled orbitals (and cancellation of the contributions of the pairs of σ and σ* and π and π* orbital pairs).
Liquid oxygen, temporarily suspended in a magnet owing to its paramagnetism
Space-filling model representation of dioxygen (O2) molecule
Oxygen discharge (spectrum) tube
Late in a massive star's life, 16O concentrates in the O-shell, 17O in the H-shell and 18O in the He-shell.
Cold water holds more dissolved.
500 million years of climate change vs. 18O
Photosynthesis splits water to liberate and fixes into sugar in what is called a Calvin cycle.
build-up in Earth's atmosphere: 1) no produced; 2) produced, but absorbed in oceans & seabed rock; 3)  starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4–5)  sinks filled and the gas accumulates
Hofmann electrolysis apparatus used in electrolysis of water.
Oxygen and MAPP gas compressed-gas cylinders with regulators
An oxygen concentrator in an emphysema patient's house
Low pressure pure is used in space suits.
Most commercially produced is used to smelt and/or decarburize iron.
Water is the most familiar oxygen compound.
Oxides, such as iron oxide or rust, form when oxygen combines with other elements.
Main symptoms of oxygen toxicity
The interior of the Apollo 1 Command Module. Pure at higher than normal pressure and a spark led to a fire and the loss of the Apollo 1 crew.

Oxygen is the chemical element with the symbol O and atomic number 8.

The 4n decay chain of 232Th, commonly called the "thorium series"


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The 4n decay chain of 232Th, commonly called the "thorium series"
Thorium dioxide has the fluorite crystal structure. Th4+: __ / O2−: __
Crystal structure of thorium tetrafluoride Th4+: __ / F−: __
Sandwich molecule structure of thorocene
Piano-stool molecule structure of (\h{8}C8H8)ThCl2(THF)2
Estimated abundances of the 83 primordial elements in the Solar system, plotted on a logarithmic scale. Thorium, at atomic number 90, is one of the rarest elements.
The radiogenic heat from the decay of 232Th (violet) is a major contributor to the earth's internal heat budget. Of the four major nuclides providing this heat, 232Th has grown to provide the most heat as the other ones decayed faster than thorium.
Thor's Fight with the Giants (1872) by Mårten Eskil Winge; Thor, the Norse god of thunder, raising his hammer Mjölnir in a battle against the giants.
Jöns Jacob Berzelius, who first identified thorium as a new element
World War II thorium dioxide gas mantle
Glenn T. Seaborg, who settled thorium's location in the f-block
The Indian Point Energy Center (Buchanan, New York, United States), home of the world's first thorium reactor
Yellowed thorium dioxide lens (left), a similar lens partially de-yellowed with ultraviolet radiation (centre), and lens without yellowing (right)
Experiment on the effect of radiation (from an unburned thorium gas mantle) on the germination and growth of timothy-grass seed

Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90.

Iron, shown here as fragments and a 1 cm3 cube, is an example of a chemical element that is a metal.


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Material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well.

Material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well.

Iron, shown here as fragments and a 1 cm3 cube, is an example of a chemical element that is a metal.
A metal in the form of a gravy boat made from stainless steel, an alloy largely composed of iron, carbon, and chromium
Gallium crystals
A metal rod with a hot-worked eyelet. Hot-working exploits the capacity of metal to be plastically deformed.
Samples of babbitt metal, an alloy of tin, antimony, and copper, used in bearings to reduce friction
A sculpture cast in nickel silver—an alloy of copper, nickel, and zinc that looks like silver
Rhodium, a noble metal, shown here as 1 g of powder, a 1 g pressed cylinder, and a 1 g pellet
A sample of diaspore, an aluminum oxide hydroxide mineral, α-AlO(OH)
A neodymium compound alloy magnet of composition Nd2Fe14B on a nickel-iron bracket from a computer hard drive
A pile of compacted steel scraps, ready for recycling
The Artemision Bronze showing either Poseidon or Zeus, c. 460 BCE, National Archaeological Museum, Athens. The figure is more than 2 m in height.
De re metallica, 1555
Platinum crystals
A disc of highly enriched uranium that was recovered from scrap processed at the Y-12 National Security Complex, in Oak Ridge, Tennessee
Ultrapure cerium under argon, 1.5 gm
White-hot steel pours like water from a 35-ton electric furnace, at the Allegheny Ludlum Steel Corporation, in Brackenridge, Pennsylvania.
A Ho-Mg-Zn icosahedral quasicrystal formed as a pentagonal dodecahedron, the dual of the icosahedron
Body-centered cubic crystal structure, with a 2-atom unit cell, as found in e.g. chromium, iron, and tungsten
Face-centered cubic crystal structure, with a 4-atom unit cell, as found in e.g. aluminum, copper, and gold
Hexagonal close-packed crystal structure, with a 6-atom unit cell, as found in e.g. titanium, cobalt, and zinc
Niobium crystals and a 1 cm{{sup|3}} anodized niobium cube for comparison
Molybdenum crystals and a 1 cm{{sup|3}} molybdenum cube for comparison
Tantalum single crystal, some crystalline fragments, and a 1 cm{{sup|3}} tantalum cube for comparison
Tungsten rods with evaporated crystals, partially oxidized with colorful tarnish, and a 1 cm{{sup|3}} tungsten cube for comparison
Rhenium, including a 1 cm{{sup|3}} cube
Native copper
Gold crystals
Crystalline silver
A slice of meteoric iron
alt=Three, dark broccoli shaped clumps of oxidised lead with grossly distended buds, and a cube of lead which has a dull silvery appearance.| oxidised lead
A brass weight (35 g)
A droplet of solidified molten tin
alt=A silvery molasses-like liquid being poured into a circular container with a height equivalent to a smaller coin on its edge| Mercury being
Electrum, a natural alloy of silver and gold, was often used for making coins. Shown is the Roman god Apollo, and on the obverse, a Delphi tripod (circa 310–305 BCE).
A plate made of pewter, an alloy of 85–99% tin and (usually) copper. Pewter was first used around the beginning of the Bronze Age in the Near East.
A pectoral (ornamental breastplate) made of tumbaga, an alloy of gold and copper
Arsenic, sealed in a container to prevent tarnishing
Zinc fragments and a 1 cm{{sup|3}} cube
Antimony, showing its brilliant lustre
Bismuth in crystalline form, with a very thin oxidation layer, and a 1 cm{{sup|3}} bismuth cube
Potassium pearls under paraffin oil. Size of the largest pearl is 0.5 cm.
Strontium crystals
Aluminum chunk, 2.6 grams, {{nowrap|1=1 x 2 cm}}
A bar of titanium crystals
Scandium, including a 1 cm{{sup|3}} cube
Lutetium, including a 1 cm{{sup|3}} cube
Hafnium, in the form of a 1.7 kg bar

A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.

A neutron-induced nuclear fission event involving uranium-235


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A neutron-induced nuclear fission event involving uranium-235
Various militaries use depleted uranium as high-density penetrators.
The most visible civilian use of uranium is as the thermal power source used in nuclear power plants.
Uranium glass glowing under UV light
Uranium ceramic glaze glowing under UV light Design and developed by Dr. Sencer Sarı
Uranium glass used as lead-in seals in a vacuum capacitor
The planet Uranus, which uranium is named after
Antoine Henri Becquerel discovered the phenomenon of radioactivity by exposing a photographic plate to uranium in 1896.
Cubes and cuboids of uranium produced during the Manhattan project
The mushroom cloud over Hiroshima after the dropping of the uranium-based atomic bomb nicknamed 'Little Boy'
Four light bulbs lit with electricity generated from the first artificial electricity-producing nuclear reactor, EBR-I (1951)
U.S. and USSR/Russian nuclear weapons stockpiles, 1945–2005
Uraninite, also known as pitchblende, is the most common ore mined to extract uranium.
The evolution of Earth's radiogenic heat flow over time: contribution from 235U in red and from 238U in green
Citrobacter species can have concentrations of uranium in their cells 300 times the level of the surrounding environment.
Uranium production 2015
Monthly uranium spot price in US$ per pound. The 2007 price peak is clearly visible.
Reactions of uranium metal
Uranium in its oxidation states III, IV, V, VI
Uranium hexafluoride is the feedstock used to separate uranium-235 from natural uranium.
Cascades of gas centrifuges are used to enrich uranium ore to concentrate its fissionable isotopes.
World uranium production (mines) and demand<ref name="WNA-WUM" />
alt=A yellow sand-like rhombic mass on black background.|Yellowcake is a concentrated mixture of uranium oxides that is further refined to extract pure uranium.

Uranium is a chemical element with the symbol U and atomic number 92.

Daniel Rutherford, discoverer of nitrogen


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Daniel Rutherford, discoverer of nitrogen
The shapes of the five orbitals occupied in nitrogen. The two colours show the phase or sign of the wave function in each region. From left to right: 1s, 2s (cutaway to show internal structure), 2px, 2py, 2pz.
Table of nuclides (Segrè chart) from carbon to fluorine (including nitrogen). Orange indicates proton emission (nuclides outside the proton drip line); pink for positron emission (inverse beta decay); black for stable nuclides; blue for electron emission (beta decay); and violet for neutron emission (nuclides outside the neutron drip line). Proton number increases going up the vertical axis and neutron number going to the right on the horizontal axis.
Molecular orbital diagram of dinitrogen molecule, N2. There are five bonding orbitals and two antibonding orbitals (marked with an asterisk; orbitals involving the inner 1s electrons not shown), giving a total bond order of three.
Solid nitrogen on the plains of Sputnik Planitia on Pluto next to water ice mountains
Structure of [Ru(NH3)5(N2)]2+ (pentaamine(dinitrogen)ruthenium(II)), the first dinitrogen complex to be discovered
Mesomeric structures of borazine, (–BH–NH–)3
Standard reduction potentials for nitrogen-containing species. Top diagram shows potentials at pH 0; bottom diagram shows potentials at pH 14.
Nitrogen trichloride
Nitrogen dioxide at −196 °C, 0 °C, 23 °C, 35 °C, and 50 °C. converts to colourless dinitrogen tetroxide at low temperatures, and reverts to  at higher temperatures.
Fuming nitric acid contaminated with yellow nitrogen dioxide
Schematic representation of the flow of nitrogen compounds through a land environment
A container vehicle carrying liquid nitrogen.

Nitrogen is the chemical element with the symbol N and atomic number 7.

Spectral lines of helium


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Spectral lines of helium
Sir William Ramsay, the discoverer of terrestrial helium
The cleveite sample from which Ramsay first purified helium
Historical marker, denoting a massive helium find near Dexter, Kansas
The helium atom. Depicted are the nucleus (pink) and the electron cloud distribution (black). The nucleus (upper right) in helium-4 is in reality spherically symmetric and closely resembles the electron cloud, although for more complicated nuclei this is not always the case.
Binding energy per nucleon of common isotopes. The binding energy per particle of helium-4 is significantly larger than all nearby nuclides.
Helium discharge tube shaped like the element's atomic symbol
Liquefied helium. This helium is not only liquid, but has been cooled to the point of superfluidity. The drop of liquid at the bottom of the glass represents helium spontaneously escaping from the container over the side, to empty out of the container. The energy to drive this process is supplied by the potential energy of the falling helium.
Unlike ordinary liquids, helium II will creep along surfaces in order to reach an equal level; after a short while, the levels in the two containers will equalize. The Rollin film also covers the interior of the larger container; if it were not sealed, the helium II would creep out and escape.
Structure of the helium hydride ion, HHe+
Structure of the suspected fluoroheliate anion, OHeF−
The largest single use of liquid helium is to cool the superconducting magnets in modern MRI scanners.
A dual chamber helium leak detection machine
Because of its low density and incombustibility, helium is the gas of choice to fill airships such as the Goodyear blimp.

Helium (from ἥλιος) is a chemical element with the symbol He and atomic number 2.